Lithium, lithium aluminum hydride, titanium trichloride and promoter for olefin polymerization



United States Patent Ofiice 3,304,295 Patented Feb. 14, 1967 LITHIUM,LITHIUM ALUMINUM HYDRIDE, TlTA- NIUM TRICHLQRIDE AND PROMOTER FOR OLEFINPOLYMERIZATION Hugh J. Hagemeyer, In, and Marvin B. Edwards, Longview,Tex., assignors t Eastman Kodak Company, Rochester, N.Y., a corporationof New Jersey No Drawing. Filed July 13, 1964, Ser. No. 382,351

18 Claims. (Cl. 260-935) This application is a continuation-in-part ofcopending US. application Serial No. 28,826, filed May 13, 1960.

This invention relates to the polymerization of hydrocarbons andcatalysts useful for this purpose. More particularly, this inventionrelates to the catalytic polymerization of a-monoolefinic hydrocarbonscontaining at least 3 carbon atoms to form solid, highly crystallinepolymers using a catalyst mixture that is highly stereospecific at hightemperatures.

It is well known that in the catalytic polymerization of a-olefinichydrocarbons such as propylene or butene, it is possible to producepolymers having widely different properties and physical characteristicsdepending, to a large extent, upon the catalyst system and the processconditions. Much of the work in this field has been directed to thedevelopment of catalysts and catalytic processes that are capable offorming highly crystalline polymers, i.e., those having crystallinitiesof at least 70%, since it has been shown that these highly crystallinepolymers have greatly improved properties over the completely orpredominately amorphous polymers. For example, amorphous polypropylenethat has been formed as a solid by some of the methods known in the arthas a melting point of only 80 C. and a density of 0.85 while solid,highly crystalline polypropylene has a melting point of at least 165 C.and a density of 0.92. Similarly, crystalline polybutene-l has a meltingpoint of 120 C. and a density of 0.91 Whereas the amorphous polybutene-lhas a softening point of about 60 C. and a density of 0.87. This sameincrease in density and melting point is observed with other wolefins insolid polymeric form including both the straight and branched chaina-monoolefins. Thus, crystalline poly(3-methylbutene-1) has a meltingpoint in excess of 240 C., crystalline poly(4- methylpentene-l) has amelting point in excess of 205 C., crystalline poly (4-methylhexene-1)has a melting point of about 190 C., crystalline poly(5-methylhexene-1)has a melting point of the order of 130 C. and crystallinepoly(4,4-dimethylpentene-1) has a melting point in excess of 300 C. Itis apparent, therefore, that polymerization processes and catalysts thatwill form highly crystalline polymers from rx-olefinic hydrocarbons,i.e., those polymers having crystallinities of at least 70%, are ofconsiderable importance in the art.

A number of methods have been proposed for preparing such solid, highlycrystalline polymers including, for example, the polymerization ofethylene and higher a-olefins such as propylene and butene-l to highlycrystalline polymers in the presence of inert diluents at temperaturesof 100 C. or below and at relatively low pressures. Catalysts mixturesthat have been employed in these so called slurry processes comprise analuminum compound, e.g. an aluminum alkyl, a dialkyl aluminum halide, analkyl aluminum sesquihalide or lithium aluminum tetraalkyl and acocatalyst, e.g. a transition element halide. However, when catalysts ofthis type are used at temperatures above 100' C., the transition elementhalide is rapidly reduced and an inactive catalyst results. These priorart catalysts, therefore, cannot be used for polymerization at elevatedtemperatures which would permit formation of the polymer near or aboveits melting point, without fouling of the catalyst or inactivation ofthe system. Furthermore, elevated temperatures would also obviate thedifficulties inherent in many of the lower temperature processes whereinthe formation of the polymer causes a deposit on the catalyst sufiicientto cause inactivation or, Where the polymerization is carried out in asolvent medium, the polymerization mixture becomes too viscous foradequate agitation before the catalyst is exhausted with a resultantloss in the economy of the process and a necessity for removing largeamounts of residual catalyst from the resulting polymer.

Another advantage of higher temperatures over lower temperatures in thepolymerization of a-olefinic hydrocarbons is that the induction time fora catalyst decreases as the temperature rises. Thus, Natta et a1. givedata in La Chimica e lIndustria 39, paragraph 12 (No. 12) 1002-1012(1957), specifically in FIGURE 5, which demonstrates that an increase inthe temperature from 32 C. to C. shortens the time required to approacha constant rate of polymerization from 7 hours to 2 hours. Attemperatures of at least C. and preferably C. this induction period issubstantially eliminated, provided, of course, that the catalyst is notinactivated at these high temperatures. It is also significant that,Natta, in the same series of articles, points out that catalyst such asaluminum alkyls and titanium trichloride give lower crystallinities athigher temperatures.

Still another significant advantage of high temperature solutionpolymerization processes over the low temperature slurry processes isthat, in the former, the catalyst concentrations are generally so lowthat it is possible to simply filter the polymer solution to obtainproducts with residual ash contents low enough to be satisfactory formost commercial uses. In contrast, it is exceedingly difiicult toseparate a solid by chemical reaction and extraction which must be usedin the low temperature slurry processes. Furthermore, separation of acatalyst by filtration and polymer recovery by melt concentration inthese high temperature processes avoids contamination of recycle olefinand solvent streams with polar solvents such as alcohols which areemployed in the low temperature slurry processes to wash out thecatalyst from the polymer. Polar solvents such as alcohols are, ofcourse, catalyst poisons, and, therefore, the recycle olefin and solventstreams in a low temperature slurry process must be vigorously purifiedto remove these polar contaminants. In a high temperature solutionprocess, however, the monomer and solvent streams can be merelyfiltered, concentrated and recycle-d directly to the synthesis stepwithout extensive purification treatments which are so necessary in thelow temperature slurry processes.

It is also known that many crystalline polymers of aolefinichydrocarbons are not suitable for many low temperature applications dueto their poor brittle points. Brittle point is the temperature at whicha polymer exhibits brittle failure under specific impact conditions asmeasured, for example, by ASTM D746-55T. Thus, crystalline polypropyleneprepared by conventional prior art procedures generally exhibits abrittle point of about 20 C. which severely restricts its utility in lowtemperature applications such as packaging of frozen foods.

It is evident, from the discussion hereinabove, that the state of theart will be greatly enhanced by a catalytic polymerization process forthe preparation of solid, highly crystalline polymers at elevatedtemperatures. Likewise, a noteworthy contribution to the art will be acatalyst that is effective at elevated temperatures to form solid, highmolecular weight u-olefinic hydrocarbon polymers having improvedproperties, particularly low temperature properties;

7 It is accordingly an object of this invention to provide a novelprocess for the polymerization of a-olefinic hydrocarbons to highmolecular weight polymers and particularly to solid, high molecularweight polymers having very high crystallinities, i.e., crystallinitiesof at least 70%.

Another object of this invention is to provide a novel process for thepolymerization of a-olefinic hydrocarbons to high molecular weight,highly crystalline polymers at elevated temperatures.

Another object of this invention is to provide a novel polymerizationprocess that employs a catalytic mixture which, unlike closely relatedmixtures, is highly effective for polymerizing a-olefinic hydrocarbonsto solid polymer having improved physical properties and which possessan unusual degree of stereospecificity whereby objectionable formationof low molecular weight polymers that are oily or greasy in nature isavoided and whereby the formation of amorphous solid polymer is alsolargely obviated.

Another object of this invention is to provide a novel polymerizationprocess that employs a catalyst composed of at least three componentsthat gives results which can be reproduced, has a long life and giveshigh polymer to catalyst yields.

Another object of the invention is to facilitate the commericalproduction of very highly crystalline solid polymer whereby hydrocarbonpolymers of very high softening points, high tensile characteristics,good moldability, improved stiifness and film forming properties arereadily obtained.

Other objects will be apparent from the description and claims whichfollow.

In accordance with this invention, it has been found that a-olefinichydrocarbons containing at least 3 carbon atoms can be polymerized atelevated temperatures to solid, high molecular weight polymer havingimproved properties and crystallinities of at least 70% in the presenceof a catalyst comprising (i) lithium metal, (2) lithium aluminum hydrideand (3) a halide of a transition metal from Group IVBVIB of the PeriodicTable, in which the valence of the metal is at least one less thanmaximum.

This novel process is extremely effective for polymerizing oc-OlCfiHiChydrocarbons containing at least 3 carbon atoms and particularly thestraight and branched chain aliphatic or aromatic ot-rnonoolefinichydrocarbons containing 3 to carbon atoms to form solid, high molecularweight, highly crystalline polymer in excellent yield. The polymerizableot-olefinic hydrocarbons suitable for use in the practice of thisinvention include, for example, propylene, butene-l, pentene-l,octene-l, decene-l, 3- methyl-l-butene, 4-methyl-1-pentene,4-methyl-1-hexene, S-methyl-l-hexene, 4,4-dimethyl-1-pentene, styrene,ccmethylstyrene, allylcyclohexane, allylcyclopentane, allylbenzene andsimilar u-olefinic hydrocarbons containing at least 3 carbon atoms. Inpracticing the invention, such a-olefinic hydrocarbons can bepolymerized alone, in ad- .mixture or sequentially with each other orwith other polymerizable hydrocarbons such as ethylene.

It is possible to employ either lithium metal or lithium aluminumhydride with transition element halides as catalysts for the hightemperature polymerization of a-olefinic hydrocarbons at elevatedtemperatures. However, lithium is a high melting alkali metal (meltingpoint 186 C.) and at the elevated temperatures generally employed forthe'polymerization of a-olefinic hydrocarbons 'it is extremely difficultto duplicate lithium dispersions. Since the availability of lithium informing the active catalyst with the transition element halide is afunction of the particle size and dispersion of lithium, there isconsiderable variation from one batch of catalyst to another withresultant difficulty in controlling the polymerization reaction.Furthermore, lithium aluminum hydride is an extremely reactive agent andis susceptible to destruction not only by temperature but also byimpurities such as carbon monoxide, carbon dioxide, water and othersubstances which are normally present in the monomer and solventstreams. In contrast, catalyst mixtures of lithium, lithium aluminumhydride and the aforementioned transi tion element halides can beduplicated from batch to batch to obtain reproduceable results for agiven set of conditions of temperature and pressure.

Another advantage which is realized by employing mixtures of lithurn andlithium aluminum hydride rather than either component alone is that muchhigher crystallinities and molecular weights are obtained in thepolymerization process. Furthermore, the catalyst systems of thisinvention are extremely rugged and exhibit a long life which isparticularly important in continuous processing. Still anothersignificant feature of the catalyst of this invention is that catalystresidue can be separated by any suitable mechanical means such ascentrifugation or filtration and recycled to the polymerizationreaction.

It is important to note that both lithium and lithium aluminum hydridecomponents of the catalyst act as cocatalysts in combination with thetransition element halides. This is shown by a definite effect uponinherent viscosity when the mole ratio of either one is changed whileholding the other constant, as illustrated by the following examples,particularly Example 3.

As already indicated, one component of the catalyst is lithium metal andanother component of the catalyst mixture is lithium aluminum hydride.These catalyst components are combined with at least one subvalenthalide of a transition metal from Group IVBVIB of the Periodic Table toform the active catalyst. The Periodic Table referred to herein can befound in Langes Handbook of Chemistry, 8th Edition (1952), published byHandbook Publishers, Inc., at pages 56 and 57.

The transition metals included in Groups IV-B, V-B and VI-B of thePeriodic Table are exemplified by titanium, zirconium, vanadium,molybdenum, chromium and the like. The preferred transition metals arethose having molecular Weights in the range of about 47 to about 52, Le,titanium, vanadium or chromium. The metals in these metal polyhalidesexhibit a valence which is at least one less than maximum. It ispreferred that the titanium halides such as titanium trichloride, ortribromide be employed in the practice of this invention. These halidescan be prepared by any suitable method. Thus, titanium trichloride, forexample, can be prepared by reducing titanium tetrachloride withhydrogen, alkali metals or other metals such as aluminum, titanium,antimony and the like. Transition metal halides other than titaniumhalides which give good results include, for example, vanadiumtrichloride, vanadium dichloride, molybdenum dichloride, tungstendibromide, zirconium trichloride, chromium dichloride and the like. Thecatalyst components are generally employed in mole ratios of the lithiumand lithium aluminum hydride components, based on lithium content, totransition metal halide in the range of about 1:2 to about 10:1; withpreferred mole ratios being in the range of about 1:1 to about 4:1.

The components referred to hereinabove make up the effective catalystfor the process. However, the stereospecificity of the catalyst can beimproved by employing another component which, by itself, is not aneffective catalyst for the reaction. These additional components oftenlead to the preparation of polymers of higher molecular Weight for agiven polymerization temperature and it is advantageous to employ themin practicing this invention. Such additional components are exemplifiedby alkali metal halides such as sodium or potassium fluoride, and oxidesor lower alkoxides of calcium, magnesium or aluminum such as magnesiumoxide, calcium oxide, aluminum ethoxide, aluminum isopropoxide or thelike. The lower alkyl groups in the alkoxides generally contain up toabout 4 carbon atoms and include methyl, ethyl, butyl and the like. Thefluorides are the preferred alkali metal halides but the chlorides oriodides are suitable. These additional catalyst components are usuallyemployed in mole ratios in the range of about 0.1:10, and preferably0.25:5, based on the transition metal subhalide.

The polymerization in accordance with this invention is generallycarried out at pressures in the range of about atmospheric to about2,000 atmospheres. Usually pressures greater than 15 atmospheres, andpreferably in the range of about 15 to 300 atmospheres, are employed toobtain commercially satisfactory rates. Higher pressures are generallyrequired for the polymerization in the absence of a solvent. In theabsence of a solvent, the gas dissolved in the polymer should generallybe from 1 to 4 times the weight of the polymer in order to obtainviscosities that can be handled satisfactorily in the reactor space.Increasing the quantities of dissolved gas lowers the viscosity in thereactor space which allows for better heat transfer and good catalystdistribution. The pressure in the polymerization can be achieved in anydesirable manner, a convenient method being to pressure the system whichthe monomer or monomers being polymerized.

The polymerization reaction can be carried out in the presence orabsence of an inert organic liquid vehicle. When the polymerization iscarried out in the presence of an inert organic liquid vehicle, thisvehicle can be any of the inert organic liquids which contain nocombined oxygen and which are free of water, alcohol, ether or othercompounds containing oxygen or compounds containing unsaturation. Theorganic vehicle employed can be an aliphatic alkane or cycloalkane suchas pentane, hexane, heptane or cyclohexane, or a high molecular weightliquid paraffin or mixture of paraffins which are liquid at the reactiontemperature, or an aromatic hydrocarbon such as benzene, toluene, xyleneor the like, or a halogenated aromatic compound such as chlorobenzene. Apetroleum fraction of suitable boiling range such as odorless mineralspirits (a sulfuric acid washed parafiinic hydrocarbon boiling at about180200 C.) will give particularly good results. In addition, goodresults can be obtained when the polymerization is carried out in thepresence of a dense gas such as highly compressed propylene by operatingat elevated pressures.

The catalyst mixtures of this invention are extremely effective atelevated temperatures. Thus, the polymerization reaction can be carriedout at temperatures in the range of about 140 C. to about 300 C. andpreferably at temperatures in the range of about 150 C. to about 250 C.At these high temperatures the catalyst is employed in concentrations ofabout 0.01 to about 5%, by weight, based on the monomer beingpolymerized, with preferred catalyst concentrations being in the rangeof about 0.1 to about 1%, by weight. Lower catalyst concentrations canbe employed, but generally the rate of polymer formation is quite slowand at higher catalyst concentrations considerable difficulty isencountered in controlling the reaction. The concentration of thecatalyst employed will generally depend upon the desired method ofoperation, for example, low catalyst concentrations would be used wherehigh polymer to catalyst yields are desired. On the other hand, highcatalyst concentrations are employed where high polymer yields per unitof reactor space are desired.

The process of this invention makes it possible to prepare a highlycrystalline polymer, i.e. one exhibiting a crystallinity in excess of70, 80 or even 90%. The crystallinity of the product can be determinedby extrac- 6 tion or X-ray diffraction techniques that are well known inthe art. For example, the crystallinity of polypropylene is determinedby refluxing the polymer in hexane, the portion of the solid polymerinsoluble in refluxing hexane being the crystalline portion.

This invention can be further illustrated by the following examples ofpreferred embodiments thereof although it will be understood that theseexamples are included merely for purposes of illustration and are notintended to limit the scope of the invention unless otherwisespecifically indicated:

Example I As already indicated, a catalyst comprising lithium metal,lithium aluminum hydride and a Group IVB- VI-B transition metalsubhalide is an effective catalyst for the polymerization of ana-monoolefinic hydrocarbon, either alone, in admixture and in sequencewith other polymerizable monomers at elevated temperatures.

To illustrate, propylene is compressed to 1250 to 1500 atmospheres andfed, at rates varying from 8,600 to 14,100 pounds per hour, into anelongated reactor 14 feet long with 20 inches internal diameter, whichreactor is separated into two distinct reaction zones by a centrallylocated bafile. The reactor also has a stirring mechanism extendingthrough the two reaction zones. In the top zone the agitator shaft thatextends through the center of the reactor is provided with a single4-bladed paddle type agitator at the top of the zone. In the second zonemixing paddles are placed substantially along the entire length of theagitator shaft to give a plug flow with a minimum of back mixing fromthe second to the first zone.

A catalyst consisting of 3.26 parts, by Weight, of lithium metaldispersion, 0.17 part, by weight, lithium aluminum hydride and 14.3parts, by weight, titanium trichloride slurried in cyclohexane, is fedat rates varying from 0.2 to 0.45 pound per hour. The temperature in thefirst zone is controlled by external cooling and by controlling the rateof feed and temperature of the incoming propylene. Conversions in thefirst zone are generally controlled at 20-40% by controlling thepropylene feed rate and the catalyst concentration employed.

In the second zone, ethylene is fed to give a feed rate varying from to1,000 pounds per hour to obtain a polymer having a crystallinity, shownby extraction in boiling hexane, in excess of 70%. The results of fourruns using the above procedures are set forth in the following table.

TABLE I Run No 1 2 3 4 Propylene feed to first zone, lbs./hr 10,80012,100 8 900 7 300 3.2 Li, 0.17 LiAlH4, 14.3 TiOl; Catalyst feed, lbs/hr0. 23 0. 46 0. 31 0. 41 Reactor pressure, atms 1, 270 1, 300 1, 250 1,500 Reactor temperatures, 0.:

First zone top.-." 168 174 178 First zone bottom 193 191 193 Second zonetop 190 192 196 199 Second zone bottom 186 190 199 206 Ethylene feed tosecond zone, lbs/hr. 230 380 360 310 Production rate, lbs/hr 3, 360 4,020 2, 170 2, 420 Inherent viscosity (tetralin, 145 0.). 2. 57 2. 31 2.42 2. 68 Percent ethylene in polymer 2.1 3. 9 7. 9.0 Bnttlenesstemperature, C 25 41 60 60 Example 2 The catalyst employed in theprocess of this invention can contain additional components such asalkali metal halides or oxides or alkoxides of calcium, magnesium oraluminum. To illustrate, a mixture comprising 9 g. of lithium metal,12.4 g. of lithium aluminum hydride, 100 g. of titanium trichloride and27 g. of sodium fluoride is charged to an 80-.gallon autoclavecontaining 42.5 gallons of mineral spirits. A feed of 50 volume percentpropylene, 47 volume percent butene-l, and 3 volume percent propane ispumped in until the pressure is 400 p.s.i. The

7 8 polymerization is run at 150 C. for 12 hours. The TABLE IIIpolymerizate is filtered and concentrated to yield 56 pounds ofpropylene-l-butene copolymer having an in- Runs Crystalline herentviscosity in tetralin at 145 C. of 1.55 (0.25% Properties pconcentration). The percent of l-butene in the polymer 1 2 3 Pyle is42%.

Example 3 Reaction Temper ature, C 173 168 160 As pointed outhereinabove, the lithium and lithium 123 gfigfifLQ-fffi 242 76 1,56 M2aluminum hydride act as co-catalysts in combination with InherengViSJOSitY in Tetralin 9 n h ran i i n m l h li as wn y' definite efiect10 n is iigfjijjjjIIIIiIIIII 0.313? Gilli 0.5023 (tin upon inherentviscosity when the concentration of either l hgs fi g -i +0 one ischanged while holding the other one constant. To iiff ggfififl g fit 56f 0 0 illustrate, a series of 3 runs is made in an 80-gallon stirred(Notched) 74 01 Izod Impact Strength at 23 C. autoclave, usmg propyleneas the monomer. The polym- (Unnotched) (l) 1 (l) 16 erization is run ata temperature of 160 C. and a pressure of 400 p.s.i.g. for 12 hours. 40gal. of mineral spirits is 1 N0 break employed as the solvent. Theresults are as follows:

TABLE II Catalyst Components, Mole Ratio Inherent Percent v CatalystLbs. Poly- Vlscosity 1n Crystallmity Run No. Charge. mer/Lb. Tetralin at(Hexane Li LiAlH TiCl NaF Grams Catalyst 145 C. Extracti n) It can beseen from the above table that the polymers Example 4 prepared accordingto the practice of this invention exhibit improved properties, andparticularly, lower brit- The Polymerization of 'dlefihic hydrocarbonsSuch as tle points which are significantly lower than those gen-Pfopylehe according m the Process of this invention gives erallyassociated with commercial crystalline polyproa P l having improvedPhysical P p p pylene. It can readily be seen that the tensile strengthsly brittle point, tensile impact strength, and notched Izod d Izodimpact strengths of polymers prepared d. impact Strength To illustrate,a Series Of Crystalline P Y- ing to the practice of this invention alsoshow a marked P PY P yp p which are insoluble in improvement incomparison to commercial crystalline fluxin-g hexane, are prepared in acontinuous system empolypropylene, ploying two SOD-gallon stirredreactors in series. In the Example 5 first stirred reactor the feed ismineral spirits solvent, propylene and catalyst. The catalyst is a2:0.5:1:1 mix- Any of the a-monoolefinic hydrocarbons, and particture oflithium, lithium aluminum hydride, titanium triularly those containing2-10 carbon atoms, can be polymchloride and magnesium oxide. Thepolymerization is erized according to the practice of this invention. Tocarried out at 160 C. at 1,000 p.s.i.g. The feed rates are illustrate, aseries of runs are made in a 2-liter stirred adjusted to give a polymercontent of 20-35%. The autoclave employing 5 g. of 2:0.5:1:1 molemixture of efiluent from the first reactor passes to the second stirredlithium metal, lithium aluminum hydride, titanium trireactor whereadditional solvent and propylene are added chloride and sodium fluoridesuspended in cyclohexane at rates to maintain solids content at 30-38%and propylwith some of these hydrocarbons. The polymerization one at18-23%. conditions and results are set forth in the following table.

TABLE IV Polymerization Condi- Percent tions Crystallinity Inherent RunNo. Monomer Yield, (percent Viscosity g. insoluble in Tetralin Temp., 0.Pressure in boiling at 145 C.

pentane) Butene-l 170 1, 250 263 84 2. 04 Butene-l 163 1,200 143 76 2.41 4MethylPentene-1 170 1,200 169 80 2. 25 Butene-l 160 1, 200 298 S8 2.65

Similar results are obtained when other ot-olefinic un- From the secondreactor the polymer solution i let saturated hydrocarbons, especiallythe a-monoolefinic hydown to a dilution tank at p.s.i.g. where unreacteddrocarbons, are substituted for the monomers employed propylene isflashed oii and recycled mineral spirits is in the above procedure.Thus, the substitution of proadded to give a 10% polymer solution. The10% polypylene, pentene, decene, allylcyclohexane or allylcyclomer dopeis filtered and then concentrated by stripping pentane, tor the abovemonomers, gives polymers having with hot propylene at 200 C. Thepolypropylene is exgood physical properties and crystallinities inexcess of trudecl through water and chopped into Aa-inch pellets. Thepellets are extracted with hexane at 69 C. for 12 Example 6 hours togive an 88% Yield of crystalline p yp py 70 The titanium chlorides arethe preferred transition The Properties this Polymer together With two pymetal halides used in the catalysts employed in the pracmefs p p at andare Set forth in tice of the process of this invention. However, any ofthe the following table. 7 For comparison purposes, the proptransitionmetal halides from Groups IV-B--VIB of erties of a commercialcrystalline polypropylene are also the Periodic Table in which the metalhas a valence at set forth. i least one less than maximum are suitable.To illustrate,

9 a series of runs are made in a 2-liter stirred autoclave using acatalyst charge of 4 g. in each run. The monomer employed is propyleneand the results are as follows.

10 It can be seen from the above table that the catalyst employed in thepractice of this invention results in a polymer having significantlyimproved properties. In ad- TABLE V Polymerization Conditions PercentInherent Catalyst Mole Ratlo Yield, Crystallinity Viscosity Componentsof Comg. (percent inin Tetralin ponents Temp., C. Pressure Solventsoluble in at 145 C.

boiling hexane) 2:0. 5:111 165 1, 000 Mineral spirits 210 91 2. 49}2:0.5:1:0.5 170 1,180 185 88 2.61 2:0. 5:110. 5 168 1, 000 Cyclohexane96 93 2.10

Similar results are obtained with subhalides of any of the transitionmetals of Group IVBVIB of the Periodic Table. The most suitable metalsare those having atomic weights in the range of about 47 to about 52,i.e., titanium, vanadium and chromium, although molybdenum or tungstenalso give good results.

Example 7 Polymers prepared using mixtures of lithium and lithiumalumium hydride with transition metal halides give polymers exhibitingmarkedly improved physical properties in comparison to polymers preparedusing either lithium or lithium aluminum hydride singly with atransition metal halide. To illustrate, four systems, i.e., (l) lithiummetal, titanium trichloride and sodium fluoride, (2) lithium aluminumhydride, titanium trichloride and sodium fluoride, 3) lithium metal,lithium aluminum hydride, titanium trichloride and sodium fluoride and(4) lithium metal, lithium aluminum hydride and titanium trichloride areemployed to polymerize propylene. The same solvent and type of titaniumtrichloride are employed in all of these runs and the lithiumdispersions and lithium aluminum hydrides are from the same source. Thetemperature is controlled at 160 -2 C., and the pressure at 400120p.s.i.g. 40 g. of titanium trichloride is used as the standard chargeand the other components are added in an amount' found to give optimummole dition, it can be seen that the catalyst has a significantly longerlife.

Thus, by the practice of this invention there is provided to the art aspecific catalyst mixture which can be employed at elevated temperatures.to form solid, high molecular weight, highly crystalline polymers fromocolefinic hydrocarbons containing at least 3 carbon atoms. Thecomponents of the catalyst mixture are readily available materials andare easily handled in commercial operations which makes them readilyadapted to commercial scale production. The polymers that are obtainedin acc-ordance with the practice of this invention can be used forforming film, molded articles, coated articles and the like, whichproducts exhibit improved low temperature properties. They can beblended with other plastic materials or compounded with pigments, dyes,fillers, stabilizers and the like. The process of this invention isapplicable to forming copolymers, both random and block, from a-olefinscontaining at least 3 carbon atoms and a variety of products can bereadily obtained by varying the relative proportions of the componentsin the mixtures of monomers being polymerized.

Although the invention has been described in considerable detail withreference to certain preferred embodiments thereof, it will beunderstood that variations and modifications can be efiected Withoutdeparting from ratios. The results of these runs are set forth in thefolthe spirit and scope of the invention as described hereinlowingtable. above and .as defined 1n the appended claims.

TABLE VI Properties of Percent Crystalline Init. Effective CrystallinityInherent Polypropylene Catalyst Mole Ratio of Cat. Catalyst (percentV1scos1ty Components Components Act. Life, Hrs. insoluble ID. Tetralinin boiling at 145 C. Brit. Tensile hexane) Temp, Impact 0. Strength 1Initial Catalyst Activity, Grams Polymer] Gram Catalyst/Hour.

We claim: I

1. The process for polymerizing an m-monoolefinic hydrocarbon containingat least 3 carbon atoms to solid, high molecular weight polymer having acrystallinity of at least 70% which comprises contacting saidu-monoolefinic hydrocarbon, at a temperature in the range of about 140to about 300 C. and a pressure in the range of atmospheric to about 2000atmospheres with a catalyst comprising (1) lithium metal, (2) lithiumaluminum hydride and (3) a halide of a transition metal from GrouplV-B-VI-B of the Periodic Table, the valence of the metal in said halidebeing at least one less than maximum, the mole ratio of (l) and (2),based on lithium content, to (3) 'being in the range of about 1:2 toabout :1.

2. The process for polymerizing an a-monoolefinic hydrocarbon containingat least 3 carbon atoms to solid, high molecular weight polymer having acrystallinity of at least 70% which comprises contacting saida-monoolefinic hydrocarbon, at a temperature in the range of about 140to about 300 C. and a pressure in the range of atmospheric to about 2000atmospheres wit-h a catalyst comprising (1) lithium metal, (2) lithiumaluminum hydride, (3) a halide of a transition metal from Group 1VB-VIBof the Periodic Table, the valence of the metal in said halide being atleast one less than maximum and (4) a member selected from the groupconsisting of a halide of .an alkali metal, an oxide of a metal selectedfrom the group consisting of calcium, magnesium, and aluminum and alower alkoxide of a metal selected from the group consisting of calcium,magnesium and aluminum, the mole ratio of 1) and (2), based on lithiumcontent, to (3) being in the range of about 1:2 to about 10:1 and themole ratio of (4) to (3) being in the range of about 01:10 to about0.25:5.

3. The process for polymerizing an a-monoolefinic hydrocarbon containing3-10 carbon atoms to solid, high molecular weight polymer having acrystallinity of at least 70%, which comprises contactingsaid-a-monoolefinic hydrocarbon, at a temperature in the range of about140 to about 300 C. and a pressure in the range of about atmospheric toabout 2000 atmospheres, with a catalyst comprising (1) lithium metal,(2) lithium aluminum hydride and (3) a halide of a transition metal fromGroup IV-BVIB of the Periodic Table, said metal having an atomic weightof about 47 to about 52, the valence of the metal in said halide beingat least one less than maximum, the mole ratio of (1) and (2), based onlithium content, to (3) being in the range of about 1:1 to about 4: 1.

4. The process for polymerizing an a-IHOBOOlCfiniC hydrocarboncontaining 3-10 carbon atoms to solid, high molecular weight polymerhaving .a crystallinity of at least 70% which comprises contacting saidm-monoolefinic hydrocarbon, at a temperature in the range of about 140to about 300 C. and a pressure in the range of atmospheric to about 2000atmospheres, with a catalyst comprising (1) lithium metal, (2) lithiumaluminum hydride, (3) a halide of a transition metal, said metal havingan atomic weight in the range of about 47 to about 52, the valence ofthe metal in said halide being at least one less than maximum and (4) amember selected from the group consisting of a halide of an alkalimetal, an oxide of a metal selected from the group consisting ofcalcium, magnesium and aluminum and a lower alkoxide of a metal selectedfrom the group consisting of calcium, magnesium and aluminum, the moleratio of (1) and (2), based on lithium content, to (3) being in therange of about 1:1 to about 4:1 and the mole ratio of (4) to (3) beingin the range of about 0.1210 to about 0.25:5.

5. The process for polymerizing an u-m'onoole-finic hydrocarboncontaining at least 3 carbon atoms to solid, high molecular weightpolymer l1 aving a crystf u iy of at least 70%, which comprisescontacting said m-mo no' about to about 250 C. and a pressure in therange of about 15 to about 300 atmospheres with a catalyst com-prising(1) lithium metal, (2 lithium aluminum hydride and (3) a halide of atransition metal from Group IV-B-VI-B of the Periodic Table, the valenceof the metal in said halide being at least one less than maximum, themole ratio of (l) and (2), based on lithium content, to (3) being in therange of about 1:2 to about 10:1.

6. The process for polymerizing an a-monoolefinic hydrocarbon containingat least 3 carbon atoms to solid, high molecular Weight polymer having acrystallinity of at least 70% which comprises contacting saidtX-IIlOIlO- olefin-ic hydrocarbon, at a temperature in the range of about 140 to about 300 C. and a pressure in the range of atmospheric toabout 2000 atmospheres with a catalyst comprising (1) lithium metal, (2)lithium alu- IlliDUtlIl hydride, (3) a halide of a transition metal fromGroup lV-BVIB of the Periodic Table, the valence of the metal in saidhalide being at least one less than maximum and (4) a member selectedfrom the group consisting of a halide of an alkali metal, an oxide of ametal selected from the group consisting of calcium, magnesium andaluminum and a lower alkoxide of a metal selected from the groupconsisting of calcium, magnesium and aluminum, the mole ratio of (1) and(2), based on lithium content, to (3) being in the range of about 1:2 toabout 10:1 and the mole ratio of (4) to (3) being in the range of about0.1210 to about 0.25:5.

7. The process for polymerizing propylene to solid, high molecularweight polymer having a crystallinity of 70%, which com-prisescontacting said a-m0n0olefinic hydrocarbon, at a temperature in therange of about 140 to about 300 C. and a pressure in the range ofatmospheric to about 2000 atmospheres with a catalyst comprising (1)lithium metal, (2) lithium aluminum hydride, (3) a halide of atransition metal from Group IV-BVIB of the Periodic Table, the valenceof the metal in said halide being at least one less than maximum and (4)a member selected from the group consisting of a halide of an alkalimetal, an oxide of a metal selected from the group consisting ofcalcium, magnesium and aluminum and a lower alkoxide of a metal selectedfrom the group consisting of calcium, magnesium and aluminum, the moleratio of (1) and (2), based on lithium content, to (3) \being in therange of about 1:2 to about 10:1 and the mole ratio of (4) to (3) beingin the range of about 01:10 to about 0.25:5.

8. The process for polymerizing propylene to solid, high molecularweight polymer having a crystallinity of at least 70% which comprisescontacting said propylene, at a temperature of about C. and a pressureof about 400 p.s.i. g., with a catalyst comprising (1) lithium metal,(2) lithium aluminum hydride, (3) titanium trichloride and (4) sodiumfluoride, the mole ratio of (1):(2):(3):(4) being about 22051111.

9. The process for polymerizing propylene to solid, high molecularWeight polymer having a crystallinity of at least 70% which comprisescontacting said propylene, at a temperature of about C. and a pressureof about 1,000 p.s.i.g., with a catalyst comprising (1) lithium metal,(2) lithium aluminum hydride, (3) vanadium trichloride and (4) magnesiumoxide, the mole ratio of (1):(2):(3):(4) being about 210.52111.

10. The process for polymerizing propylene to solid, high molecularweight polymer having a crystallinity of at least 70% which comprisescontacting said propylene, at a temperature of about 168 C. and apressure of about 1,000 p.s.i.g., with a catalyst comprising (1) lithiummetal, (2) lithium aluminum hydride, (3) chromium dichloride and (4)sodium fluoride, the mole ratio of (l):(2):(3):(4) being about2:0.5:1:0.5.

11. A catalyst for the polymerization of a-monoolefinic hydrocarbons to.high molecular weight, highly crystalline polymers comprising (1)lithium metal, (2) lithium aluminum hydride and (3) a halide of a tran-13 sition metal from Group IV-B-VIB of the Periodic Table, the valenceof the metal in said halide being at least one less than maximum, themole ratio of (1) and (2), based on lithium content, to (3) being in therange of about 1:2 to about :1.

12. A catalyst for the polymerization of u-monoolefinic hydrocarbons tohigh molecular weight, highly crystalline polymers comprising (1)lithium metal, (2) lithium aluminum hydride, (3) a halide of atransition metal from Group IVB--VIB of the Periodic Table, the valenceof the metal in said h-alide being at least one less than maximum and(4) a member selected from the group consisting of a halide of an alkalimetal, an oxide of a metal selected from the group consisting ofcalcium, magnesium and aluminum and a lower alkoxide of a metal selectedfrom the group consisting of calcium, magnesium and aluminum, the moleratio of (1) and (2), based on lithium content, to (3) being in therange of about 1:2 to about 10:1 and the mole ratio of (4) to (3) beingin the range of about 01:10 to about 0.25 :5.

13. A catalyst for the polymerization of a-monoolefinic hydrocarbons tohigh molecular weight, highly crystalline polymers comprising (1)lithium metal, (2) lithium aluminum hydride and (3) a halide of atransition metal from Group IV-B-VIB of the Periodic Table, said metalhaving an atomic weight of about 47 to about 52, the valence of themetal in said halide being at least one less than maximum, the moleratio of (1) and (2), based on lithium content, to (3) being in therange of about 1:1 to about 4:1.

14. A catalyst for the polymerization of u-monoolefinic hydrocarbons tohigh molecular weight, highly crystalline polymers comprising (1)lithium metal, (2) lithium aluminum hydride, (3) a halide of atransition metal, said metal having an atomic weight in the range ofabout 47 to about 52, the valence of the metal in said halide being atleast one less than maximum and (4) a member selected from the groupconsisting of a halide of an alkali metal, an oxide of a metal selectedfrom the group consisting of calcium, magnesium and aluminum and a loweralkoxide of a metal selected from the group consisting of calcium,magnesium and aluminum, the mole ratio of (1) and (2) based on lithiumcontent, to (3) being in the range of about 1:1 to about 4:1 and themole ratio of (4) to (3) being in the range of about 0.1:10 to about0.25:5.

15. A catalyst for the polymerization of u-monoole- 14 finichydrocarbons to high molecular weight, highly crystalline polymerscomprising (1) lithium metal, (2) lithium aluminum hydride and (3) ahalide of la transition metal from Group IV-BVI-B of the Periodic Table,the valence of the metal in said halide being at least one less thanmaximum, the mole ratio of (1) and (2), based on lithium content, to (3)being in the range of about 1:2 to about 10:1.

16. A catalyst for the polymerization of a-monoolefinic hydrocarbons tohigh molecular weight, highly crystalline polymers comprising (1)lithium metal, (2) lithium aluminum hydride, (3) a halide of atransition metal from Group IV-B-VI-B of the Periodic Table, the valenceof the metal in said halide being at least one less than maximum and (4)a member selected from the group consisting of a halide of an alkalimetal, an oxide of a metal selected from the group consisting ofcalcium, magnesium and aluminum and a lower alkoxide of a metal selectedfrom the group consisting of calcium, magnesium and aluminum, the moleratio of (1) and (2), based on lithium content, to (3) being in therange of about 1:2 to about 10:1 and the mole rat-i0 of (4) to (3) beingin the range of about 0.1210 to about 0.25:5.

17. A catalyst for the polymerization of a-monoolefinic hydrocarbons tohigh molecular weight, highly crystalline polymers comprising (1)lithium metal, (2) lithium aluminum hydride, (3) titanium trichlorideand (4) sodium fluoride, the mole ratio of (1):(2):(3):(4) being about2:0.5:1:1.

18. A catalyst for the polymerization of a-monoolefinic hydrocarbons tohigh molecular weight, highly crystalline polymers comprising 1) lithiummetal, ,(2) lithium aluminum hydride, (3) vanadium trichloride and (4)magnesium oxide, the mole ratio of (1) (2) (3) :(4) being about2:0.5:1:1.

References Cited by the Examiner UNITED STATES PATENTS 2,879,261 3/1959Johnson 260--79.3 2,886,561 5/1959 Reynolds 26094.9 3,072,628 1/1963Coover 26093.7 3,125,558 3/1964 Hagemeyer 26093.7 3,149,097 9/1964Coover 26093.7

JOSEPH L. SCHOFER, Primary Examiner.

M. B. KURTZMAN, Assistant Examiner.

1. THE PROCESS FOR POLYMERIZING AN A-MONOOLEFINIC HYDROCARBON CONTAININGAT LEAST 3 CARBON ATOMS TO SOLID, HIGH MOLECULAR WEIGHT POLYMER HAVING ACRYSTALLINITY OF AT LEAST 70% WHICH COMPRISES CONTACTING SAIDA-MONOOLEFINIC HYDROCARBON, AT A TEMPERATURE IN THE RANGE OF ABOUT 140*TO ABOUT 300*C. AND A PRESSURE IN THE RANGE OF ATMOSPHERIC TO ABOUT 2000ATMOSPHERES WITH A CATALYST COMPRISING (1) LITHIUM METAL, (2) LITHIUMALUMINUM HYDRIDE AND (3) A HALIDE OF A TRANSITION METAL FROM GROUPIV-B-VI-B OF THE PERIODIC TABLE, THE VALENCE OF THE METAL IN SAID HALIDEBEING AT LEAST ONE LESS THAN MAXIMUM, THE MOLE RATIO OF (1) AND (2),BASED ON LITHIUM CONTENT, TO (3) BEING IN THE RANGE OF ABOUT 1:2 TOABOUT 10:1.